That's a thought-provoking way of putting it, though I'd add the /r/gonewild subreddit and its variants makes it considerably more meta. A lot of people, particularly females, are posting explicit imagery of themselves - revealing a hidden culture exhibitionism as the vast majority of them do it for little profit beyond comments and upvotes. There are people on Reddit who do actually make money from posting explicit content, but the vast majority of users who do it are in it for a sense of self-worth from the "updoots" and the thrill of exposing themselves relatively anonymously.
Taking your observations about advertising into account, it's a complex ecosystem. The closest thing I've seen to Reddit is Usenet, but in a age where digital cameras are ubiquitous.